Compilare: main.cpp: In function 'int main()': main.cpp:20:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<=s.size();i++) ~^~~~~~~~~~ main.cpp:28:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(pr[i]==a.size()) ans++,v.push_back(i-a.size()*2-1); ~~~~~^~~~~~~~~~ main.cpp:10:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("strmatch.in","r",stdin); ^ main.cpp:11:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("strmatch.out","w",stdout); ^